Field of the Invention
The present invention relates to a portable device and a portable timepiece.
Background Art
In a portable timepiece such as a wristwatch and a pocket watch or a portable device such as a stopwatch, a cellular phone, and a portable information terminal, a non-contact charging method has been widely introduced in which a charger is not directly connected by a wire and electromagnetic induction is alternatively utilized, for example. The non-contact charging method employs a power supply coil disposed in the charger for non-contact charging and a power receiving coil disposed inside a housing of the portable device.
For example, the charger used for the non-contact charging method in this way includes the power supply coil and a cover plate. For example, the portable device has the power receiving coil incorporated inside the housing. If the portable device is brought close to the cover plate in a state where electricity is supplied to the power supply coil of the charger, the electromagnetic induction is generated between the power supply coil and the power receiving coil, thereby generating power (induced electromotive force) on the power receiving coil side. In the portable device, a storage battery incorporated in the portable device is charged with the power generated in the power receiving coil.
In order to perform charging by using the non-contact charging method, it is preferable to bring the power supply coil and the power receiving coil close to each other. In the related art, JP-A-2011-160501 discloses an electronic device (charger) having improved charging efficiency. The electronic device includes a second coil (power supply coil). The second coil is magnetically coupled with a first coil (power receiving coil) disposed in a band portion extending in a horizontal direction of a timepiece main body of a wristwatch (portable device). The electronic device includes a positioning recess for positioning the band portion of the wristwatch. In order to charge a capacitor disposed in the wristwatch, the band portion is positioned in the positioning recess, and the charging is performed in a state where the first coil and the second coil are brought close to each other.
Incidentally, in recent years, the charger has been installed in a place other than a fixed charging place such as a user's house, and various types have been installed as the charger. Therefore, it is necessary to provide a portable device whose charging efficiency can be improved even if the portable device is charged using various chargers. However, according to the electronic device disclosed in JP-A-2011-160501, the capacitor of the wristwatch is charged after the band attached to the wristwatch is positioned in the positioning recess in the electronic device. Therefore, even if non-contact charging has to be performed on the wristwatch by using another electronic device, a charging device and a power receiving coil are less likely to be aligned with each other. Consequently, it is difficult to improve charging efficiency.